The present invention relates to a drive circuit and, for example, to a drive circuit that drives a load connected thereto.
A drive circuit for driving an external load connected thereto is mounted on various electric equipment, semiconductor devices and the like.
For example, a drive circuit to be used for bioelectrical impedance measurement is proposed (Japanese Unexamined Patent Application Publication No. 2013-12868). A living body is electrically connected as a load to this drive circuit. In this configuration, the drive circuit passes an alternating current (AC) with a constant amplitude through the living body and thereby can measure the impedance of the living body. In this example, an output terminal of a differential amplifier in the drive circuit is connected to one end of the living body, and the other end of the living body is connected to an inverting input terminal of the differential amplifier, thereby forming a feedback circuit.
Besides, a drive circuit that passes a constant current through a load (coil) is proposed (Japanese Unexamined Patent Application Publication No. 2003-204231). This drive circuit passes a current through the load by varying an output voltage with respect to a fixed voltage.